1. Field of the Invention.
This invention pertains to energy conservation, and more particularly to apparatus for reducing energy losses in buildings.
2. Description of the Prior Art.
Extensive efforts have been made in recent years to lower energy consumption. Building heat losses have drawn much attention, and numerous new construction products and methods have been developed to decrease those losses.
It is well known that a great amount of building heat is lost to the outside through conventional wall electrical outlet boxes. At the same time, cold outside air can enter a heated area through the electrical outlet boxes and thereby displace the expensive heated air. To reduce the heat losses associated with electrical outlet boxes, it is known to partially enclose them within air impervious covers. Examples of such covers may be seen in U.S. Pat. Nos. 4,158,420; 4,345,693; and 4,408,695. The various covers disclosed in those patents are made from flexible materials. The walls are quite thin and easy to cut for passing electrical wires through the walls. The covers also have flat thin-wall flanges that slant away from the cover. The prior covers have not proven entirely satisfactory. That is primarily because the slanting flanges must be pressed tightly against a building wall member, such as a gypsum board, so as to bend the flanges. The bent flanges exert a force on the wall board to create a seal between the flanges and the board surface. Bending the flanges causes them to become stressed, and the flanges and flexible cover walls therefore tend to distort. Consequently, despite exerting force on the wall board, the flanges may not seal properly, and air can flow past the flanges into and out of the heated area. Further, a builder can never be certain that an effective seal has been created, because the cover and flanges are hidden from view by the wall board.
Thus, a need exists for improved air seals around building wall electrical outlet boxes.